And .9‒ (12/14/17) 4 digit numbering stamped metal stamps for use on the side of business cards and other materials. This is a low-cost alternative to the more expensive, high quality 8 digit serial numbered number stamps, but it does take a little longer to make, so it may not be for everyone. This serial number stamp is available as a set of 3. Number stamps This stamp is a number line that allows you to add a number to each character in any writing. It will not show up on a letter if you do not write a number there. The stamp number will appear at the bottom of everything you write. Note: if you use this stamp, keep the number line off the top or bottom of your sheets because any letter you write with only the number line on the sheet will become invisible. This number stamp is a very cheap option. It comes with a few numbers (the number of digits will vary.) This is a number line that allows you to add a number to each character in any writing. It will not show up on a letter if you do not write a number there Serial numbered # Stamps This is a cheap option for a serial number stamp, it is the same thing as the one above but will be engraved. The number will be between 1 and 15. You could also add numbers by hand. Make the numbers in this order: 1 1 5 A 1 5 B 1 1 6 C 1 1 6 & D 2 3 5 A 2, 7 & E 3 4 5 & (4 + 5) B 2, 8 & F 4 5 A E. 5 6 & (4 + 6)' D 3, 9 & G Now that you know the most common options and why you shouldn't use an extra line, you'll be better able to make the perfect price tag or invoice.